\begin{flushleft}
\begin{minipage}[t]{\textwidth}
\hrulefill

\vspace*{-5mm}

\begin{verbatim}
#include<iostream.h>
#include<LINK/basic/Array.h>
#include<LINK/basic/MSet.h>
#include<LINK/basic/Set.h>

main()
{
        MSetBase<int, SortedArray<int> > mset1;
        MSet<int> mset2;                        // default impl:SortedList

        for (int i=0; i<3; i++) {
                mset1.insert(i);
                mset2.insert(i);
        }

        mset2.insert(0);
        cout<<"there are "<<mset2.occurrences(0)<<" zeros in "<< mset2<<endl;

        if (mset1.properSubsetQ(mset2))
                cout << mset1 << " is a proper subset of " << mset2 << endl;
        if (mset1.subsetQ(mset2))
                cout << mset1 << " is a subset of " << mset2 << endl;

        mset2.remove(0);

        if (mset1.properSubsetQ(mset2))
                cout << mset1 << " is a proper subset of " << mset2 << endl;
        if (mset1.subsetQ(mset2))
                cout << mset1 << " is a subset of " << mset2 << endl;

}
\end{verbatim}

\vspace*{-7mm}

\hrulefill

\vspace*{-5mm}

\begin{verbatim} 
there are 2 zeros in {0 0 1 2}
{0 1 2} is a proper subset of {0 0 1 2}
{0 1 2} is a subset of {0 0 1 2}
{0 1 2} is a subset of {0 1 2}
\end{verbatim}

\vspace*{-6mm}

\hrulefill
\end{minipage}
\end{flushleft}